Composites reinforced with thermotropic liquid crystal copolyester fibers (Celanese Vectran) have been studied with regard to fiber properties and fiber matrix adhesion. As-spun (AS) and heat-treated (HT) fibers have been characterized. Heat treatment increases the crystal-to-nematic melting point by 40 C and increases modulus 18% while doubling strength. Composites made with Vectran fibers (HT) should be processed at or below 275 C, because fiber properties are significantly reduced on processing above this temperature, which corresponds to the AS melting point. Keywords: Composites; Liquid crystal; Copolyester; Electron microscope; Fiber surface treatment; Polycarbonate.